Party: Cressida was part of the group that partied with Prince Harry prior to his now notorious trip to Las Vegas

Mr Wentworth-Stanley, 23, whose stepfather, the Marquess of Milford Haven, is a cousin of the Queen.

He and Cressida were a couple while students at Leeds University, but he went travelling after graduation and their romance cooled. In July, she was said to be 'desperate' to rekindle their relationship.

Harry, the third-in-line to the throne, and Cressida were seen embracing in July at a Batman movie premiere.

And Cressida joined Harry on a holiday to Richard Branson's Necker Island before he flew to Las Vegas for his infamous 'naked' high jinks.

Cressida's half-sister, Isabella Calthorpe, spurned Prince William's affections and is due to marry Sam Branson, the son of the Virgin tycoon Sir Richard Branson, in March.

Cressida's father is Lady Mary-Gaye's third husband, the businessman Jeffrey Bonas. They divorced when Cressida was five years old.